Deno installs unused npm dependencies despite --entrypoint flag usage

[M4RC3L05]

Given this simple project:

main.ts:

import "@std/assert";
import "express";

console.log("oioioi");

deno.json:

{
  "tasks": {
    "dev": "deno run --watch main.ts"
  },
  "imports": {
    "@std/assert": "jsr:@std/assert@1",
    "dbmate": "npm:[email protected]",
    "express": "npm:[email protected]"
  }
}

Running:

deno clean && deno install --entrypoint main.ts && du -h --max-depth=0 ~/.cache/deno/

I get the following output:

Removed /home/main/.cache/deno (1004 files, 4.63MB)
38M     /home/main/.cache/deno/

If now i edit the main.ts to comment out the import "express" line, and rerun the above command:

deno clean && deno install --entrypoint main.ts && du -h --max-depth=0 ~/.cache/deno/

i get:

Removed ~/.cache/deno (241 files, 2MB)
2,7M    ~/.cache/deno/

Checking into the files, it appears that both dbmate and express are being installed even tho i do not use dbmate directly, and since i am running the install command with --entrypoint i would expect deno to only install express.

Is my assumption correct? i would expect deno to be smart about which deps are being used and only install does.

[M4RC3L05]

This is the deno cache folder with express commented out:

And this with express being imported:

[nathanwhit]

The behavior you want was implemented in #27300, gated behind an unstable flag.

It's technically a breaking change (it can break things in some edge cases), so we didn't enable it by default. (That PR description is out of date, I ended up changing it so --entrypoint behavior was unchanged by default as well).

You can opt in with the --unstable-npm-lazy-caching flag or

"unstable": ["npm-lazy-caching"]

in deno.json

[M4RC3L05]

@nathanwhit It did worked, but if i have this:

{
  "tasks": {
    "dev": "deno run --watch main.ts"
  },
  "lock": {
    "frozen": true
  },
  "unstable": ["npm-lazy-caching"],
  "imports": {
    "@std/assert": "jsr:@std/assert@1",
    "dbmate": "npm:[email protected]",
    "express": "npm:[email protected]"
  }
}

Runnin deno clean && deno install --entrypoint main.ts && du -h --max-depth=0 ~/.cache/deno/ dbmate gets installed. Looks like it does not place nice with frozen lock files? if i set it to false it works as expected, only used deps gets installed

[M4RC3L05]

Actually after some tests it only works if you provide the flags on the command it self, setting it in the deno.json under the unstable property did not work.

[M4RC3L05]

Another update, with this deno.json and the same main.ts as above:

{
  "tasks": {
    "dev": "deno run --watch --cached-only main.ts"
  },
  "lock": {
    "frozen": false
  },
  "unstable": ["npm-lazy-caching"],
  "imports": {
    "@std/assert": "jsr:@std/assert@1",
    "dbmate": "npm:[email protected]",
    "express": "npm:[email protected]"
  }
}

Running:

deno clean && deno install --entrypoint main.ts && du -h --max-depth=0 ~/.cache/deno

I get:

Removed ~/.cache/deno (3415 files, 61.57MB)
38M     ~/.cache/deno

Which means the unstable prop did not work.

Running:

deno clean && deno install --entrypoint --unstable-npm-lazy-caching main.ts && du -h --max-depth=0 ~/.cache/deno

I get:

Removed ~/.cache/deno (1009 files, 34.22MB)
7,0M    ~/.cache/deno

If i followup this with the following command:

deno task dev

I get:

Download https://registry.npmjs.org/dbmate/-/dbmate-2.24.2.tgz
Download https://registry.npmjs.org/@dbmate/linux-x64/-/linux-x64-2.24.2.tgz
Task dev deno run --watch --cached-only main.ts
Watcher Process started.
Warning 'npm-lazy-caching' isn't a valid unstable feature
error: Uncaught (in promise) NotCapable: Requires read access to <CWD>, run again with the --allow-read flag
    at Process.cwd (ext:deno_fs/30_fs.js:152:10)
    at Object.<anonymous> (file:///home/main/.cache/deno/npm/registry.npmjs.org/depd/2.0.0/index.js:23:24)
    at Object.<anonymous> (file:///home/main/.cache/deno/npm/registry.npmjs.org/depd/2.0.0/index.js:540:4)
    at Module._compile (node:module:745:34)
    at loadMaybeCjs (node:module:770:10)
    at Object.Module._extensions..js (node:module:755:12)
    at Module.load (node:module:662:32)
    at Function.Module._load (node:module:534:12)
    at Module.require (node:module:681:19)
    at require (node:module:812:16)
Watcher Process failed. Restarting on file change...

Looks like deno task command just downloads everything?

If instead of running deno task i run the command directly:

deno run --watch --cached-only main.ts

I get an error and also a warning about the unstable config:

Watcher Process started.
Warning 'npm-lazy-caching' isn't a valid unstable feature
error: Failed caching npm package '[email protected]'
    0: npm package not found in cache: "dbmate", --cached-only is specified.
Watcher Process failed. Restarting on file change...

But if i add --unstable-npm-lazy-caching to it, it works:

deno run --watch --cached-only --unstable-npm-lazy-caching main.ts

output:

Watcher Process started.
Warning 'npm-lazy-caching' isn't a valid unstable feature
✅ Granted read access to <CWD>.
✅ Granted env access to "NO_DEPRECATION".
✅ Granted env access to "TRACE_DEPRECATION".
✅ Granted env access.
oioioi
Watcher Process finished. Restarting on file change...

Running deno run without the --cached-only just downloads the extra deps.

From this examples looks like the deno.json unstable prop does not seems to be picked up? also should deno task command fetch dependencies?